Grapevine leafroll-associated virus 7

Abstract

Grapevine leafroll disease (GLD) is one of the most important grapevine viral diseases affecting grapevines worldwide. The impact on vine health, crop yield, and quality is difficult to assess due to a high number of variables, but significant economic losses are consistently reported over the lifespan of a vineyard if intervention strategies are not implemented. Several viruses from the family Closteroviridae are associated with GLD. However, Grapevine leafroll-associated virus 3 (GLRaV-3), the type species for the genus Ampelovirus, is regarded as the most important causative agent. Here we provide a general overview on various aspects of GLRaV-3, with an emphasis on the latest advances in the characterization of the genome. The full genome of several isolates have recently been sequenced and annotated, revealing the existence of several genetic variants. The classification of these variants, based on their genome sequence, will be discussed and a guideline is presented to facilitate future comparative studies. The characterization of sgRNAs produced during the infection cycle of GLRaV-3 has given some insight into the replication strategy and the putative functionality of the ORFs. The latest nucleotide sequence based molecular diagnostic techniques were shown to be more sensitive than conventional serological assays and although ELISA is not as sensitive it remains valuable for high-throughput screening and complementary to molecular diagnostics.The application of next-generation sequencing is proving to be a valuable tool to study the complexity of viral infection as well as plant pathogen interaction. Next-generation sequencing data can provide information regarding disease complexes, variants of viral species, and abundance of particular viruses. This information can be used to develop more accurate diagnostic assays. Reliable virus screening in support of robust grapevine certification programs remains the cornerstone of GLD management.

Probing into the Effects of Grapevine Leafroll-Associated Viruses on the Physiology, Fruit Quality and Gene Expression of Grapes

“…Unlike other viruses of the Closteroviridae , no insect vector has been found to transmit GLRaV-7 ( Table 1 ) [ 21 ]. Its distribution is therefore attributed to the global exchange of propagating materials and vegetative propagation [ 85 ]. Isolates of GLRaV-7 have genome size of 16.4–16.5 kb with 9 (for isolate PN-23) or 10 (for isolate AA42) ORFs ( Figure 1 C) [ 3 , 79 , 80 ].…”

Quality Assessment and Validation of High-Throughput Sequencing for Grapevine Virus Diagnostics

“…Most likely because the petioles collected in spring had a low titer of the virus, as the Ct showed a high value of 29.6 (data not shown). This situation is similar to other leafroll viruses that have higher titer in the late growing season [53,54]. Likewise, virus distribution within the plant should also be considered for the inconsistency of GLRaV-7 detection.…”

List of non‐EU viruses and viroids of Cydonia Mill., Fragaria L., Malus Mill., Prunus L., Pyrus L., Ribes L., Rubus L. and Vitis L.

“…Reported from a number of countries outside the EUIt might be present but not reported in other EU MSs or outside the EUAl Rwahnih et al. (,b) Grapevine satellite virus GV‐SatXReported in the US on material of European origin, in Hungary and in France on material of Iranian originVery recently described virus from HTS data (Al Rwahnih et al, ). Significant uncertainty.…”

“…It might be present but not reported in the EUAl Rwahnih et al. (,b) Grapevine leafroll‐associated virus 13 GLRaV‐13XNot reported to be present in the EURecently described virus (2016) from HTS data on which information is very limited. It might be present but not reported in the EUIto and Nakaune () Grapevine red blotch virus GRBVXXNot reported to be present in the EUIt might be present but not reported in the EUCieniewicz et al.…”